JPH037481A - Picture input device - Google Patents

Abstract

PURPOSE:To always obtain a display picture with proper exposure by providing a means releasing an automatic adjustment function of an aperture control circuit so as to vary the aperture of an objective lens. CONSTITUTION:When there is a light with a high brightness level exists in a part of an incident light of a CCD (solid-state image pickup element) 3 under the condition that proper exposure is obtained, the aperture of an ALC lens A is operated in the closing direction. Thus, an event of darkened display picture or hard to see required pattern might be caused. Since a variable means varying the aperture manually is provided by releasing the aperture automatic adjustment function, a selection switch 10 selects the manual operation to adjust properly with a volume 9. Thus, the display picture of always proper exposure is obtained regardless of the incident light with high brightness level and illuminance object.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an image input device equipped with a solid-state image sensor such as a COD (charge-coupled device) image sensor and an automatic aperture RO description of an objective lens. .

(Prior Art) In recent years, solid-state image sensors such as CCD image sensors have been increasingly used in place of image pickup tubes in this type of image input device. Image light (incident light) is photoelectrically converted and captured, and the photoelectrically converted signal is processed in the next stage processing circuit.
It is output as a video (VIDEO) signal. that time,
In order to obtain a display image with appropriate brightness (appropriate exposure), the aperture mechanism of the objective lens is automatically controlled according to the brightness level of the incident light, and for this purpose, an ALC (auto level control) lens is used. are doing.

The IIJ control signal of the ALC lens is generated from the output of the preprocessing circuit that mixes the three primary color signals of R (red), G (green), and B (blue) from the solid-state image sensor, and this Luno control signal is sent to the aperture mechanism. By supplying the same amount of light, it is possible to always adjust the exposure to an appropriate level.

[Problem to be solved by the invention]

However, in the conventional image input device using the ALC lens as described above, if some of the light incident on the solid-state image sensor includes light with a high brightness level, control No. 43
There was a problem in that the diaphragm of the LC lens closed, and a part of the displayed image became dark and difficult to see, making it impossible to display a clear displayed image with appropriate brightness.

The present invention was made in view of these problems, and
[1] It is an object of the present invention to provide an image input device that can always display images with appropriate exposure even if part of the incident light includes light at a high brightness level.

(Means for Solving the Problems) The image input device of the present invention charges and converts image light from a subject and captures it (f solid-state image sensor and an object image sensor according to the brightness level of the incident light on the solid-state image sensor). It is equipped with an aperture control circuit that automatically adjusts the aperture amount of the lens, and a single variable stage that cancels the automatic adjustment function and makes the aperture amount of the objective lens variable.

(Function) The image input device of the present invention does not have a means for canceling the automatic aperture leaf adjustment function of the aperture control circuit to make the aperture size of the objective lens variable. Even if there is light at a certain brightness level, the exposure can be adjusted to the appropriate level.

〔Example〕

FIG. 1 is a block diagram showing the configuration of an image input device according to an embodiment of the present invention. This image input device is divided into an ALC lens A with an automatic aperture and a camera section B.

In the figure, 1 is the objective lens, 2 is its aperture mechanism, 3 is a CCD (solid-state image sensor) that photoelectrically converts image light from the subject and captures it, and 4 is the R, G, and B colorimetric signal output from the CCD 3. Sample and hold circuit that samples and holds
5 is the output of sample hold circuit 4 (from No. 15 to ALC
A pre-processing circuit generates a control signal and a Y signal (luminance signal) for the lens A, and the R signal and B signal are input to the pre-processing circuit 5 after appropriately gain adjustment using an amplifier. 6 is R-Y, B- from the output signal of the pre-processing circuit 5.
a Y color difference signal and a process circuit that generates the Y signal;
7 is an encoder circuit RY that generates and outputs an NTSC video signal from the output signal of the process circuit 6;

The B-Y color difference signal is appropriately amplified and input to the encoder circuit 7. Reference numeral 8 denotes an aperture control circuit that automatically adjusts the aperture amount of the objective lens 1 according to the brightness level of incident light on the CCD 3, and determines the aperture tl of the ALC lens A from the control signal (brightness signal) from the pre-processing circuit 5. Aperture #
The control signal is output to the first structure and the second structure. 9 is a volume for manual aperture adjustment, and IO is a selection switch used when switching between automatic and manual modes or when a sudden change in exposure occurs.The volume 9 and this selection switch IO control the aperture control circuit 8. Variable means is configured to cancel the automatic adjustment function and vary the aperture hl of the objective lens 1.

Next, the operation will be explained.

The image light from the subject that enters the CCD 3 from the ALC lens A is charged and converted here to R, G.

It is extracted as a B color signal. Each color signal is sampled and held in a sample and hold circuit 4 and sent to a preprocessing circuit 5. At this time, the sample and hold circuit 4 removes unnecessary fluctuations. In addition to the R, G, and B color signals, the preprocessing circuit generates a Y signal as a signal corresponding to the a' degree level of the incident light.
A signal of the aperture control angle of the LC lens A is generated.

R, G, B color signals from the above-mentioned pre-processing circuit 5 and Y
The signal is input to the process circuit 6, where R-Y and B-
A Y color difference signal and a Y signal are generated. Then, the encoder circuit 7 generates a video signal from these signals and outputs it to a display device outside the area.

Here, in this embodiment, the aperture control circuit 8 automatically adjusts the aperture amount of the objective lens 1 so as to provide appropriate exposure for the incident light Ift from the ALC lens A. A control signal for the aperture mechanism 2 is output based on the output signal from the pre-processing circuit 5. At this time, if there is a high brightness level in some of the incident light on the CCD 3 under conditions where proper exposure is achieved, the aperture of the ALC lens A moves in the direction of closing. The entire screen may become dark or it may become difficult to see the screen you want.However, in this embodiment, a variable means is provided that allows you to cancel the automatic adjustment function of the aperture amount and manually vary the aperture amount. Therefore, in the above case, select switch 10
You can switch to manual mode and adjust the aperture leaf appropriately using volume 9. Therefore, a properly exposed display image can always be obtained regardless of the incident light at a high brightness level or the angle of 11<1 degrees of the subject.

In the above embodiment, the aperture control circuit 8 has the following three functions, which can be switched by the selection switch 10.

a. Automatically adjust the aperture ■ according to the constantly incident light.

b. Automatic aperture: Switch from A adjustment to manual aperture adjustment when sudden exposure changes occur.

C3 Always manually adjust the aperture amount by 3AI.

Further, the aperture control circuit 8 and variable means are provided on the camera side.

〔Effect of the invention〕

As described above, according to the present invention, the automatic adjustment function of the aperture control circuit is canceled to make the aperture i) of the objective lens variable. Even if this happens, the aperture amount can be adjusted manually, which has the effect of always displaying an appropriately exposed image.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of an image input device according to an embodiment of the present invention. 1...Objective lens 2...Aperture mechanism 3-----CCD (solid-state image sensor) 4...
・Sample hold circuit 5...Buri process circuit 6---Process circuit 7...Encoder circuit 8...Aperture control circuit A---ALC lens B −11 Camera Department

Claims (1)

[Claims] It includes a solid-state image sensor that photoelectrically converts image light from the subject and captures it, an aperture control circuit that automatically adjusts the aperture of the objective lens according to the brightness level of the light incident on the solid-state image sensor, and a diaphragm control circuit that automatically adjusts the aperture amount of the objective lens according to the brightness level of the light incident on the solid-state image sensor. An image input device comprising variable means for varying the aperture amount of the objective lens.